This invention relates generally to thread connected joints as usable in oil well tubing, casing, line pipe and drill pipe (all of which will be referred to as pipe, for convenience). More particularly, it concerns a means for connecting joint pin and box members in a manner to provide minimal hoop, radial or axial stresses induced by assembly or applied torque.
With increased concern for protection of our environment, it is becoming more important that tubular joint connections used in oil industry be capable of performing with maximum security under all conditions characteristic of the operating tasks they are relied upon to fulfill. Basic fundamental technology required to meet these performances must be satisfied through all operating stress or strain levels. Today there are no tubular connections produced anywhere in the world which will meet these requirements through all operating stress or strain conditions characteristic of services to which they may be exposed. In most cases, margins of safety are inherently smaller as severity of performance increases. There is a need for a connection that will have mechanical integrity which will not be weakened by load stresses or strains induced by tension, compression, internal pressure, external pressure, torsion, bending, thermal variances, or any combination of these until the material itself has failed by limitations of metallurgical properties in rupture or fracture.